THIS INVENTION relates to diffusers.
The term xe2x80x9cdiffuserxe2x80x9d is used to designate those devices which, in air conditioning systems, are employed for the purpose of regulating flow of air, which may be heated air or cooled air, from air conditioning ducting into a room.
Various conditions occur in an air conditioned room depending on whether the outside temperature is above that at which the room is to be maintained or below that at which the room is to be maintained.
In xe2x80x9cSummerxe2x80x9d conditions cooled air is fed from the air conditioning plant to the diffuser. If the room temperature is below that at which it is desired to maintain it, because cooled air has previously been fed in, then the diffuser must remain closed to prevent further cooled air entering the room.
As the room heats up a room temperature sensing element must detect this and open the diffuser to allow more cooled air into the room. The diffuser thus opens and closes as the room temperature varies.
In xe2x80x9cWinterxe2x80x9d conditions heated air is fed to the diffuser. If the room is above the requisite temperature, because heated air has previously been fed into the room, the diffuser must remain closed to prevent further heated air entering. As the room cools down, the room temperature sensing element must detect this and open the diffuser to allow more heated air in. The diffuser consequently opens and closes as the room temperature varies.
In the specification of our South African patent 96/4791 (U.S. Pat. No. 5,647,532 and Australian Patent No. 700908) there is disclosed a diffuser which has a single room temperature sensing element which closes a diffuser when the room is too cold (in Summer conditions) and also closes the diffuser when the room is too hot (in Winter conditions). This avoids the use of complex constructions involving two or more room temperature sensing elements. The present invention seeks to provide an improved diffuser using a single room temperature sensing element. A modification of this diffuser is disclosed in our South African Patent No. 2000/1891 (U.S. Pat. No. 6,254,010 and Australian Patent Application No.28880/00)
According to one aspect of the present invention there is provided a diffuser for controlling flow of air in an air conditioning system, the diffuser including an air flow control baffle, a first temperature sensitive element for sensing room temperature variations and including a body and a piston which move relatively to one another in response to temperature variations, a second temperature sensitive element for sensing duct temperature variations and including a body and a piston which move relatively to one another in response to temperature variations, a housing, the body of one of said elements being fixed to said housing, a pair of links having inner ends and outer ends, the links being pivotally mounted on said housing at their inner ends and having their outer ends connected to said baffle, the links protruding outwardly from said housing, each link having a first cam surface on one side of its pivotal mounting and a second cam surface on the other side of its pivotal mounting, a control element having a first surface for bearing on said first cam surfaces and a second surface for bearing on said second cam surfaces, the body of the other temperature element being fast with said control element, spring means for urging said first surface towards the first cam surfaces, and a rod opposite ends of which bear on said pistons to prevent the pistons moving towards one another, the spring means, by acting on the body of said other element, holding the pistons against movement away from the ends of the rod.
According to a further aspect of the present invention there is provided a diffuser for controlling flow of air in an air conditioning system, the diffuser comprising first and second temperature sensitive elements for respectively sensing room temperature and duct temperature variations, the elements being axially aligned, a link for displacing an air flow control baffle, and a control structure for displacing said link in dependence on sensed room temperature thereby to displace said baffle and vary air flow, said control structure having a first component which acts on the link when said second element is detecting cooled air and a second component which acts on the link when the second element is detecting warmed air.
According to another aspect of the present invention there is provided a diffuser for controlling flow of air in an air conditioning system, the diffuser including an air flow control baffle, a first temperature sensitive element for sensing room temperature variations and including a body and a piston which move relatively to one another in response to temperature variations, a second temperature sensitive element for sensing duct temperature variations and including a body and a piston which move relatively to one another in response to temperature variations, a housing, the body of the first element being fixed to said housing, a pair of links having inner ends and outer ends, the links-being pivotally mounted on said housing at their inner ends and having their outer ends connected to said baffle, the links protruding in opposite directions to one another from said housing, each link having a first cam surface on one side of its pivotal mounting and a second cam surface on the other side of its pivotal mounting, a control element having a first upwardly facing surface for bearing on said second cam surfaces and a second downwardly facing surface for bearing on said first cam surfaces, the body of the first temperature element being fast with said control element, spring means for urging said second downwardly facing surface towards the first cam surfaces, and a rod opposite ends of which bear on said pistons to prevent the pistons moving towards one another, the spring means, by acting on the body of the second element, holding the pistons against movement away from the ends of the rod.
According to yet another aspect of the present invention there is provided a diffuser for controlling flow of air in an air conditioning system, the diffuser including an air flow control baffle, a first temperature sensitive element for sensing room temperature variations and including a body and a piston which move relatively to one another in response to temperature variations, a second temperature sensitive element for sensing duct temperature variations and including a body and a piston which move relatively to one another in response to temperature variations, a housing, the body of the second element being fixed to said housing, a pair of links having inner ends and outer ends, the links being pivotally mounted on said housing at their inner ends and having their outer ends connected to said baffle, the links protruding in opposite directions to one another from said housing, each link having a first cam surface on one side of its pivotal mounting and a second cam surface on the other side of its pivotal mounting, a control element having a first downwardly facing surface for bearing on said first cam surfaces and a second upwardly facing surface for bearing on said second cam surfaces, the body of the first temperature element being fast with said control element, spring means for urging said second upwardly facing surface towards the second cam surfaces, and a rod opposite ends of which bear on said pistons to prevent the pistons moving towards one another, the spring means, by acting on the body of the first element, holding the pistons against movement away from the ends of the rod.